PNNL

Abstract

Practical operation of lithium-oxygen batteries (LOBs) need to have a stable electrolyte against parasitic chemical reactions with reduced oxygen species (ROSs) as well as have high conductivity, low viscosity, high O2 solubility and low-volatility. Herein, the localized high-concentration electrolytes (LHCEs) with three fluorinated diluents were systematically investigated in comparison with conventional electrolyte in terms of their physical properties, activation energies of reaction with singlet oxygen (1O2) calculated by density functional theory (DFT) and their electrochemical performance when used in LOBs. This study demonstrates that the stability of the electrolyte (which is one of the most key factors determining the cycle life of LOBs) strongly depends on diluents in LHCEs. The selection of diluent also affects many other electrolyte properties. This work also provide new insight on the correlation between electrolyte stability and their properties (contrary to previous studies) and shin light on the rational design of new electrolytes for LOBs.